1. Field of the Invention
The present invention relates to an acceleration detector which can detect a collision of vehicle so that an air bag device, a door lock release device or a fuel-cut device can be operated and which can detect acceleration which acts on a vehicle so that suspension of the vehicle can be controlled.
2. Related Art
In this type of device, a pendulum type acceleration detector is known in Japanese Utility Model Laid-open No. 49-92274 in the past. In this prior art, when acceleration acts on a movable body, the movable body rocks and one end of a micro-switch installed thereabove is raised by rocking.
However, in the prior art, a fixed clearance exists between the movable body and the micro-switch and the movable body can rock freely in response to acceleration which acts thereon. Since a clearance exists between the movable body and the micro-switch, the movable body contacts with a leaf spring in a wide range in accordance with the direction of acting acceleration. If a contact position of the movable body and the leaf spring changes in a wide range, a reaction force by the leaf spring restricting the rock of the movable body also changes. Therefore, dispersion of the force necessary to operate the micro-switch becomes large and an acceleration level at which the acceleration detector operates becomes unstable.
Since the movable body can rock freely in response to acceleration acting thereon, even if acceleration smaller than the necessary acceleration to operate the micro-switch acts, the movable body rocks and unnecessary sound and abrasion of the movable body are produced. Moreover, in the prior art, since the movable body is composed of a pendulum and a flange which supports the pendulum, structure of the movable body becomes complicated.